package basic;

import java.util.Scanner;

public class Calculate {
    static public class NumberRangeException extends Exception{
        public NumberRangeException(){
            System.out.println("Error!");
        }
    }
    public static void main(String[] args) throws NumberRangeException {
        Scanner s=new Scanner(System.in);
        double a=s.nextDouble();
        if (a<=0)
            throw new NumberRangeException();
        double b=s.nextDouble();
        if (b<=0)
            throw new NumberRangeException();
        System.out.println(a+b);
    }
}
